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Concept: Polygonaceae


The rhizome of Polygonum cuspidatum SIEB. et ZUCC. (Polygonaceae, PC), a widely used Chinese medicine, is commonly prescribed for the treatments of amenorrhea, arthralgia, jaundice, abscess, scald and bruises.

Concepts: Pharmacology, Resveratrol, Ming Dynasty, Fallopia, Polygonaceae, Tang Dynasty


Japanese knotweed s.l. are some of the most invasive plants in the world. Some genotypes are known to be tolerant to the saline concentrations found in salt marshes. Here we focus on tolerance to higher concentrations in order to assess whether the species are able to colonize and establish in highly stressful environments, or whether salt is an efficient management tool. In a first experiment, adult plants of Fallopia japonica, Fallopia × bohemica and Fallopia sachalinensis were grown under salt stress conditions by watering with saline concentrations of 6, 30, 120, or 300 g L(-1) for three weeks to assess the response of the plants to a spill of salt. At the two highest concentrations, their leaves withered and fell. There were no effects on the aboveground parts at the lowest concentrations. Belowground dry weight and number of buds were reduced from 30 and 120 g L(-1) of salt, respectively. In a second experiment, a single spraying of 120 g L(-1) of salt was applied to individuals of F. × bohemica and their stems were clipped to assess the response to a potential control method. 60 % of the plants regenerated. Regeneration was delayed by the salt treatment and shoot growth slowed down. This study establishes the tolerance of three Fallopia taxa to strong salt stress, with no obvious differences between taxa. Their salt tolerance could be an advantage in their ability to colonize polluted environments and to survive to spills of salt.

Concepts: Water, Chemistry, Plant stem, Extinction, Fallopia, Polygonaceae, Japanese knotweed, Stem vegetables


Japanese knotweed Fallopia japonica is an extremely abundant invasive plant in Belgium and surrounding countries. To date, no eradication method is available for land managers facing the invasion of this rhizomatous plant. We tested different chemical herbicides with two application methods (spraying and stem injection), as well as mechanical treatments, on knotweed clones throughout southern Belgium. The tested control methods were selected to be potentially usable by managers, e.g., using legally accepted rates for herbicides. Stem volume, height and density reduction were assessed after one or two years, depending on the control method. Labor estimations were made for each control method. No tested control method completely eradicated the clones. Stem injection with glyphosate-based herbicide (3.6 kg ha(-1) of acid equivalent glyphosate) caused the most damage, i.e., no sprouting shoots were observed the year following the injection. The following year, though, stunted shoots appeared. Among the mechanical control methods, repeated cuts combined with native tree transplanting most appreciably reduced knotweed development. The most efficient methods we tested could curb knotweed invasion, but are not likely to be effective in eradicating the species. As such, they should be included in a more integrated restoration strategy, together with prevention and public awareness campaigns.

Concepts: English-language films, Plant stem, Fallopia, Polygonaceae, Japanese knotweed, Weed, Herbicide, Roundup


BACKGROUND: Buckwheat flour and buckwheat sprouts possess antioxidant properties, and previous studies have reported on buckwheat flour displaying an inhibitory activity for angiotensin-I converting enzyme (ACE). Information is lacking on the bioactivity of other parts of the buckwheat, such as the seed hulls and plant stalks. This study investigates the ACE inhibitory activity and antioxidant activity of various parts of 2 types of buckwheat, namely, common buckwheat (Fagopyrum esculentum Moench) and tartary buckwheat (Fagopyrum tataricum Gaertn). METHODS: For high throughput screening, we used a microplate fluometric assay to evaluate the ACE inhibitory effects of various extracts and the ferric-reducing antioxidant power (FRAP) assay to evaluate antioxidant activity. RESULTS: The extract of common hulls extracted using 50% (v/v)-ethanol solvent presented a remarkable inhibitory activity. The value of IC50 is 30 g ml-1. The extracts of both common and tartary hulls extracted using 50% (v/v)-ethanol solvent demonstrated an antioxidant activity that is superior to that of other extracts. CONCLUSION: This study determined that the ethanolic extract of the hulls of common buckwheat presented more favorable antioxidant and ACE inhibitory abilities. However, the correlation of antioxidant activity and ACE inhibitory activity for all 18 types of extracts is low. The ACE inhibitory activity could have been caused by a synergistic effect of flavonoids or from other unidentified components in the extracts. The ethanolic extract of common hulls demonstrated remarkable ACE inhibitory activity and is worthy of further animal study.

Concepts: Antioxidant, Starch, Pasta, Polygonaceae, Rutin, Buckwheat, Fagopyrum, Tartary Buckwheat


To investigate the impact of Se on Tartary buckwheat (Fagopyrum tataricum Gaertn.) plants, the plant foliage was sprayed with 10 mg Se(VI) L(-1) at the beginning of flowering. The Se was effectively assimilated by the plants and taken into the seeds, where its concentration was more than double that in untreated plants. The seeds were collected and sown to obtain the progeny of these Se-treated plants. To assess the physiological characteristics of control plants and these Se-treated progeny plants, the estimated respiratory potential via electron transport system (ETS) activity and the photochemical efficiency of photosystem II were measured. Three weeks after germination, the Se-treated progeny plants showed higher ETS activity compared to the controls. Through weeks 4 and 5, this high ETS activity approximately halved, and the difference in ETS activity seen at 3 weeks was lost. On the other hand, at week 4, the potential photochemical efficiency was higher in the Se-treated progeny plants than the controls. In adult plants, the leaves dry mass was significantly greater in the Se-treated progeny plants than the controls. This study demonstrates an impact of Se in Tartary buckwheat on the progeny plants of Se sprayed plants, as shown previously in pea plants.

Concepts: Photosynthesis, Mitochondrion, Fruit, Seed, Polygonaceae, Buckwheat, Fagopyrum, Tartary Buckwheat


A simple and rapid method for determining emodin, an active factor presented in tartary buckwheat (Fagopyrum tataricum), by high-performance liquid chromatography coupled to a diode array detector (HPLC-DAD) has been developed. Emodin was separated from an extract of buckwheat on a Kromasil-ODS C18 (250 mm × 4.6 mm × 5 μm) column. The separation is achieved within 15 min on the ODS column. Emodin can be quantified by using external standard method detecting at 436 nm. Good linearity is obtained with correlation coefficient exceeding 0.9992. The detection limit and the quantification limit are 5.7 and 19 μg/L respectively. This method shows good reproducibility for the quantification of the emodin with relative standard deviation value of 4.3%. Under optimized extraction conditions, the recovery of emodin was calculated as > 90 %. The validated method is successfully applied to quantify the emodin in tartary buckwheat and its products.

Concepts: Scientific method, Chromatography, High performance liquid chromatography, Analytical chemistry, Polygonaceae, Buckwheat, Fagopyrum, Tartary Buckwheat


Rheum rhabarbarum (rhubarb) has long been used for the treatment of inflammation in China and other Asian countries. However, the mechanism underlying the anti-inflammatory activity of this medicinal plant is not fully understood.

Concepts: Immune system, Inflammation, Anti-inflammatory, Anthraquinone, Polygonaceae, Rhubarb


Using bioengineering techniques to restore areas invaded by Fallopia japonica shows promising results. Planting tree cuttings could allow both rapidly re-establishing a competitive native plant community and reducing F. japonica performance. However, F. japonica has been shown to affect native plant species through different mechanisms such as allelopathy. This article investigates the phytotoxic effect of F. japonica on the resprouting capacity and the growth of three Salicaceae species with potential value for restoration. An experimental design which physically separates donor pots containing either an individual from F. japonica or bare soil from target pots containing cuttings of Populus nigra, Salix atrocinerea or Salix viminali was used. Leachates from donor pots were used to water target pots. The effects of leachates were evaluated by measuring the final biomass of the cuttings. F. japonica leachates inhibited the growth of cuttings, and this effect is linked to the emission of polyphenol compounds by F. japonica. Leachates also induced changes in soil nitrogen composition. These results suggest the existence of allelopathic effects, direct and/or indirect, of F. japonica on the growth of Salicaceae species cuttings. However, the three species were not equally affected, suggesting that the choice of resistant species could be crucial for restoration success.

Concepts: Effect, Affect, Resveratrol, Willow, Fallopia, Polygonaceae, Japanese knotweed, Salicaceae


We propose a mathematical model for biocontrol of the invasive weed Fallopia japonica using one of its co-evolved natural enemies, the Japanese sap-sucking psyllid Aphalara itadori. This insect sucks the sap from the stems of the plant thereby weakening it. Its diet is highly specific to F. japonica. We consider a single isolated knotweed stand, the plant’s size being described by time-dependent variables for total stem and rhizome biomass. It is the larvae of A. itadori that damage the plant most, so the insect population is described in terms of variables for the numbers of larvae and adults, using a stage-structured modelling approach. The dynamics of the model depends mainly on a parameter h, which measures how long it takes for an insect to handle (digest) one unit of F. japonica stem biomass. If h is too large, then the model does not have a positive equilibrium and the plant biomass and insect numbers both grow together without bound, though at a lower rate than if the insects were absent. If h is sufficiently small, then the model possesses a positive equilibrium which appears to be locally stable. The results based on our model imply that satisfactory long-term control of the knotweed F. japonica using the insect A. itadori is only possible if the insect is able to consume and digest knotweed biomass sufficiently quickly; if it cannot, then the insect can only slow down the growth which is still unbounded.

Concepts: Insect, Hemiptera, Fallopia, Polygonaceae, Japanese knotweed, Invasive species, Weed, Polygonum


Concern has been expressed over societal losses of plant species identification skills. These losses have potential implications for engagement with conservation issues, gaining human wellbeing benefits from biodiversity (such as those resulting from nature-based recreational activities), and early warning of the spread of problematic species. However, understanding of the prevailing level of species identification skills, and of its key drivers, remains poor. Here, we explore socio-demographic factors influencing plant identification knowledge and ability to classify plants as native or non-native, employing a novel method of using real physical plants, rather than photographs or illustrations. We conducted face-to-face surveys at three different sites chosen to capture respondents with a range of socio-demographic circumstances, in Cornwall, UK. We found that survey participants correctly identified c.60% of common plant species, were significantly worse at naming non-native than native plants, and that less than 20% of people recognised Japanese knotweed Fallopia japonica, which is a widespread high profile invasive non-native in the study region. Success at naming plants was higher if participants were female, a member of at least one environmental, conservation or gardening organisation, in an older age group (than the base category of 18-29 years), or a resident (rather than visitor) of the study area. Understanding patterns of variation in plant identification knowledge can inform the development of education and engagement strategies, for example, by targeting sectors of society where knowledge is lowest. Furthermore, greater understanding of general levels of identification of problematic invasive non-native plants can guide awareness and education campaigns to mitigate their impacts.

Concepts: Species, Plant, Fern, Plants, Extinction, Fallopia, Polygonaceae, Japanese knotweed